Centrifuge



June 26, 1962 M. KRON 3,040,899

CENTRIFUGE Filed Sept. 13, 1957 8 a 71 a a 1o 9 F I 1H1 20 INVENTOR: MAX KRON 07 WMXQJM nite States 3,040,899 CENTRIFUGE Max Kron, Zurich, Switzerland, assignor t Etablissement Mexy, Vaduz, Liechtenstein Filed Sept. 13, 1957, Ser. No. 683,756 Claims priority, application Germany Sept. 18, 1956 6 Claims. (Cl. 210-364) This invention concerns centrifugal driers and relates more particularly to driers for domestic use as well as for use in laundries.

The object of the invention is to provide a centrifugal drier of simple and robust construction which is simple in use, of relatively low weight and of small bulk so that it may be readily transported from room to room and used where most convenient. This requirement is particu larly of importance in the home.

Another object of the invention is to provide a drier in which disturbances due to vibration are reduced or eliminated so that the drier may be used in flats without disturbing neighbours.

According to this invention a centrifugal drier comprises a motor-driven centrifuging drum within a housing, the drum being fixedly mounted in relation to the driving motor and to the housing wherein the drier is arranged to rotate about a substantially vertical axis and is 'so placed or mounted on a resilient base as to be capable of oscillatiiig and gyrating about said axis.

According to a feature of the present invention the greater part of the weight of the drier is applied to the resilient base in the region of said axis and, according to another feature of the invention, the margin of the housing engages said resilient base so that a relatively small part of the weight of the drier is applied to the base through said margin.

It is preferred that the driving motor is beneath the housing and projects therefrom so that it rests on the resilient base, the motor being on said vertical axis and forming the central support for the drier.

A practical application of the present invention will now be described, byway of example only, with reference to the accompanying drawings whereof the single FIG- URE is a vertical sectional elevation of a centrifugal drier according to the invention.

Referring to the drawings: the drier comprises a drum, having a side wall '1 and a bottom wall 2, and arranged within a housing, the drum being driven by an electric motor which is carried by the housing. The drum 1, 2 is fixedly mounted on the motor 5 and thus is fixed in relation to the housing which carries the motor.

The housing is in two parts comprising a main side wall 7 and a bottom portion 8, the two parts being joined together as at 13. The side wall 7 is of convex form on the outside while the bottom 8 of the housing is formed with a dome which extends to within the housing, the dome being of conical outline and diverging in the downward direction. The driving motor 5 is bolted or otherwise secured to the undersurface of a flat portion of the dome so that it lies Within the dome, the bottom of the motor projecting from beneath the lowest marginal edge 10 of the housing.

A driving spindle 12 of the motor 5 extends upwardly to within the housing and the drum is secured to the hous ing through the agency of a boss 4, the boss being bolted to the drum and being secured to the spindle 12 by a screw 16 which lies within a recess in the boss, the recess being closed by a plate 17 which protects the screw against corrosion and provided a smooth contour for the boss 4.

The drum is in two parts and comprises a side wall 1 and a bottom 2. The wall 1 is of conical form and diverges in the downward direction and the bottom 2 is in the form of a dome which overlies the dome of the hous- 3,040,899 Patented June 26, 1962 ing. The dome of the drum is of conical form and diverges in the downward direction and is formed with a fiat top to which the boss 4 is secured. The plate 17 may be secured to the boss 4 in any known or convenient manner but it is preferred that the plate be fixed to the boss by adhesives so that a seal is provided which prevents unauthorized dismantling of the apparatus. The cover plate may form a name-plate or carry other information.

The dome 2 extends to a considerable distance within the centrifugal drum and the boss 4 further increases this extension. The domed portion within the centrifugal drum ensures that the clothes to be dried are inserted in to an annular space between the domed portion and the conical wall 1 and thereby the annular distribution of the clothes within the drum is assisted. Water discharge holes 3 are provided in the centrifugal drum at the point of maximum diameter, or substantially so, which is at the junction between the conical wall 1 and the dome 2. The holes 3 are in a region in which the clothes, during centriguing, are unlikely to be lodged so that drainage of water through the holes will not be interfered with. Moreover, the holes *3 are provided in a region representing the maximum diameter of the wall 1 and of the dome 2 so that there is a natural tendency for the water to be carried towards the discharge opening 3.

Water discharges from the centrifugal drum into'the housing 7, 8 and collects in the bottom thereof. The water Within the housing is drained through a tube 9 which is, for example, made of natural rubber or a synthetic resin having resilient properties so that the tube can not be broken when the drier is transported from one place to another. The tube 9, however, is preferably readily detachable from the housing so that it can be replaced if desired. To this end the tube 9 is formed with a rim having an annular recess so that the rim can be forced into a hole in the bottom 8, the marginal edge of the bottom around the hole entering the annular recess. This assembly is relatively cheap so that the manufacturing costs of the drier are kept down. An extension pipe may readily be fitted to the tube 9 and to prevent the pipe from inadvertently coming away from the tube the latter is formed, at its outer end, with an inwardly directed lip 20 to engage a shoulder in the pipe.

The overlap joint 13 between the wall 7. of the housing and the bottom 8 is above the drain tube 9 so that moisture will not collect at the joint.

The portion 10 of the bottom 8 forms a water trough with which the drainage tube 9 communicates.

A labyrinth seal 19 is formed between a downward extension of the boss 4 and the top bearing of the electric motor 5, the seal preventing admission of water to the motor shaft and the bearing therefor. The labyrinth seal 19 is a considerable distance above the discharge holes 3 and is also a considerable distance above the level of water which will collect in the bottom 8 of the housing. This disposition of the seal 19 together with the general arrangement of the bottom of the centrifugal drum substantially prevents Water from being thrown upwardly so that the risk of moisture entering the motor 5 and its bearings is largely avoided.

The recess 11 beneath the dome of the housing is sufficiently large as to provide a space around the electric motor 5 such that any moisture deposited on the outside of the motor can readily dry off. Moreover, the space, is such that the motor is readily accessible and -is adequately cooled. Since the electric motor 5 lies within the dome of the housing it is not exposed to view and consequently the motor casing customarily employed with centrifugal driers as hitherto made is no longer required.

Because of the conical form of the several parts of 3 the housing and of the centrifugal drum it is possible to store these parts by stacking them one within the other so that the space occupied atthe factory or during transport is small. This feature is particularly important when exporting parts of the drier for subsequent assembly.

The overall size of the drier is kept low by ensuring that the space between the drum and the housing is kept low as is evident from FIG. 1 of the accompanying drawmugs.

The motor 5 is the heaviest part of the centrifugal ldrier and since it is arranged centrally of the drier and at the bottom thereof the centre of gravity of the drier is low.

The drier rests upon a resilient base comprising a circular cushion 6 made, for example, from foamed rubber. Because the electric motor 5 projects beyond the undersurface of the bottom 8 of the housing the weight of the motor is directly applied to the centre of the cushion. The electric motor sinks into the cushion to a certain extent and as a result of this, the portion of the cushion 6 beneath the motor 5 is compressed, thus making this portion somewhat less resilient than the remainder of the cushion around the outside thereof and upon which remainder the marginal edges it? of the housing rest. Consequently, the marginal edges of the housing are supported by the cushion with greater yieldability than that with which the central portion of the cushion supports the motor. The centrifugal drier is held in position upon the cushion without having to secure the cushion permanently to the centrifugal drier. It will be understood that the greater part of the weight of the drier is applied to the resilient base in the region of the central vertical axis, a relatively small part of the weight of the drier being applied to the resilient base by the housing. With this arrangement oscillating and gyrating movements of the drier about the vertical axis are readily performed while ensuring that the drier is adequately supported by the base 6. The oscillating and gyrating movements referred to may be due to out of balance forces produced due to the uneven distribution of clothes within the centrifugal drum or due to critical speeds of operation. If the movements referred to be come excessive the housing deforms the resilient base and there is thereby created a restoring force which ensures that such movements are kept within reasonable limits.

The ability of the drier freely to oscillate and gyrate upon the resilient base enables a lighter and less powerful electric motor to be used since the latter is not required to resist the oscillating and gyrating movements.

Because the electric motor 5 lies in part within the centrifugal drier the overall height of the drier is reduced and consequently the out of balance forces created by oscillating and gyrating movements of the drier are kept low. The dome formation of the centrifugal drum, which is provided to accommodate the corresponding dome formation of the housing which in turn is provided to receive the electric motor, results in an annular space within the drum which ensures that clothes placed in the drum will be more uniformly distributed with the drum than has been possible with centrifugal driers as hitherto made. Because of the uniform distribution of the clothes within the drier more uniform drying, under centrifugal action, is also achieved.

The downwardly divergent conical wall 1 of the drum will prevent any tendency for the clothes-in the drum to move upwardly. Consequently the weight distribution of the clothes in the drum is kept low thereby further assisting in maintaining a low center of gravity.

As shown in the FIGURE the resilient base 6 is formed with selectively placed cavities so that appropriate support is provided for the electric motor 5 and the housing regard to the restoring forces which are to be created 4 when the centrifugal drier is oscillating and gyrating about the vertical axis while in use.

While it is preferred that -the resilient base be made of foamed rubber or synthetic resin it may, however, be in the form of a hollow resilient member enclosing air to form an air cushion.

Because of the low center of gravity of the centrifugal drier the forces restoring the drier when it is oscillating and gyrating about the vertical axis are due partly to the resilient base 6 and partly because there is a natural tendency for the centrifugal drier to return to its undisplaced position.

The centrifugal drum is coaxially fixed relative to the housing and there is therefore no possibility of relative movement between the drum and the housing such as would result in these members coming into contact during operation. Consequently the space between the drum and the housing may be reduced to a minimum whereby the overall size of the drier is correspondingly reduced. This is an advantage as compared with known centrifugal driers wherein the centrifugal drum was resiliently mounted and therefore unless considerable clearance was provided between the drum and the housing there was the risk that in operation the drum would come into contact with the housing.

The openings 3 pass through the overlapped edges of the conical wall 1 and the dome 2 of the centrifugal drum. The discharge openings 3 weaken the drum but as they are provided at the overlap which has adequate strength it may be arranged that the wall thickness of the centrifugal drum is reduced to a minimum without risk of weakening the drum by the discharge openings.

The dome parts 2 and 8 of the drum and housing respectively are of relatively stronger material than the parts 1 and 7 thereof.

1 claim:

1. A centrifuge consisting essentially of a housing, a centrifuging drum within the housing positioned for rotation about a substantially vertical axis, said housing having a dome-shaped bottom which projects into the housing, and the bottom of the drum having a dome overlying said housing dome, a motor having a shaft and situated within and fastened to said housing dome and projecting out of the bottom of said housing dome, said drum being mounted fixedly on the shaft of said motor, and a resilient base having a central portion on which said motor rest and which carries the main weight of said centrifuge, said resilient base having peripheral portions on which the marginal edges of said housing rest for holding the centrifuge in the upright position with greater yieldability than that with which said central portion supports said motor, whereby the motor forms a central support transmitting the greater part of the weight of the centrifuging drum, housing and motor to said base and acts as a single support point permitting gyroscopic action of the centrifuging drum when the centrifuge is running, and a relatively small part of the weight of the centrifuging drum, housing and motor is supported on the peripheral portions of said base, the peripheral portions exerting on said housing a reaction force when unbalancing forces tend to tip the housing during operation of the drum, said reaction force causing precession of the axis of rotation of said drum due to said unbalancing forces.

2. A centrifuge as claimed in claim 1, in which said drum has openings in the wall thereof for the discharge of water, said openings being provided near the bottom edge of the drum and in the immediate vicinity of the region of the drum of greatest diameter.

3. A centrifuge as claimed in claim 1, wherein the wall of the housing follows the contour of the drum and is closely spaced thereto.

4. A centrifuge as claimed in claim 1, wherein the drum is secured to the motor shaft by a boss attached to the top of said dome, said boss forming one element of a shaft seal.

5. A centrifuge as claimed in claim 1, wherein said base has regions of difierent resilience.

6. A centrifuge according to claim 5, in Which the base is of rubber-like material having in its under-surface cavities to provide said difference in resilience.

References Cited in the file of this patent UNITED STATES PATENTS Hoffbauer 2 Sept. 4, 1906 Dinsmore Sept. 13, 1910 

